Evolution of several cytoskeletal proteins of astrocytes in primary culture: Effect of prenatal alcohol exposure

Abstract

In the present work we have analyzed, using immunoblotting and immunofluorescence techniques, the evolution of several cytoskeletal proteins during the development of astrocytes in primary culture. The effect of prenatal exposure to alcohol on these proteins was also evaluated. Microtubular protein alpha-tubulin decreased approximately 47% from 4 to 7 days after which its content remained practically constant. Immunofluorescence studies showed also that the content of alpha-tubulin was greater at day 4 of culture. This increase in fluorescence was coincident with the presence of globular particles which were found in interphase astrocytes and stained with both anti alpha- and anti-beta tubulin. These structures appeared only in proliferating cells. Glial fibrillary acidic protein (GFAP) and vimentin were analyzed as intermediate filament (IF) proteins. GFAP, in cytoskeletal preparations, increased regularly for 14 days followed by a decrease to day 21. In contrast, vimentin showed a progressive increase throughout the entire culture period. Fluorescence studies revealed some differences between the IF distribution patterns of GFAP and vimentin. In astrocytes obtained from rats prenatally exposed to ethanol, decreases in the amounts of all the cytoskeletal proteins studied were found during the entire culture period. In these cells a striking disorganization of cytoskeleton was also observed. The alcohol-induced decrease of GFAP in cultured astrocytes was also found when this protein was studied in preparations from whole brain developed "in vivo".